Measurement of target and double-spin asymmetries for the ep - →eπ+(n) reaction in the nucleon resonance region at low Q2

Zheng, X.; Adhikari, K. P.; Bosted, P.; Deur, A.; Drozdov, V.; El Fassi, L.; Kang, Hyekoo; Kovacs, K.; Kuhn, S.; Long, E.; Phillips, S. K.; Ripani, M.; Slifer, K.; Smith, L. C.; Adikaram, D.; Akbar, Z.; Amaryan, M. J.; Anefalos Pereira, S.; Asryan, G.; Avakian, H.; Badui, R. A.; Ball, J.; Baltzell, N. A.; Battaglieri, M.; Batourine, V.; Bedlinskiy, I.; Biselli, A. S.; Briscoe, W. J.; Bültmann, S.; Burkert, V. D.; Carman, D. S.; Celentano, A.; Chandavar, S.; Charles, G.; Chen, J. P.; Chetry, T.; Choi, Seonho; Ciullo, G.; Clark, L.; Colaneri, L.; Cole, P. L.; Compton, N.; Contalbrigo, M.; Crede, V.; D'Angelo, A.; Dashyan, N.; De Vita, R.; De Sanctis, E.; Djalali, C.; Dodge, G. E.; Dupre, R.; Egiyan, H.; El Alaoui, A.; Elouadrhiri, L.; Eugenio, P.; Fanchini, E.; Fedotov, G.; Fersch, R.; Filippi, A.; Fleming, J. A.; Gevorgyan, N.; Ghandilyan, Y.; Gilfoyle, G. P.; Giovanetti, K. L.; Girod, F. X.; Gleason, C.; Golovach, E.; Gothe, R. W.; Griffioen, K. A.; Guidal, M.; Guler, N.; Guo, L.; Hanretty, C.; Harrison, N.; Hattawy, M.; Hicks, K.; Holtrop, M.; Hughes, S. M.; Ilieva, Y.; Ireland, D. G.; Ishkhanov, B. S.; Isupov, E. L.; Jenkins, D.; Jiang, H.; H. S., Jo; Joosten, S.; Keller, D.; Khachatryan, G.; Khandaker, M.; Kim, A.; Kim, W.; Klein, F. J.; Kubarovsky, V.; Lanza, L.; Lenisa, P.; Livingston, K.; Macgregor, I. J. D.; Markov, N.; Mckinnon, B.; Mirazita, Marco; Mokeev, V.; Movsisyan, A.; Munevar, E.; Munoz Camacho, C.; Murdoch, G.; Nadel Turonski, P.; Net, L. A.; Ni, A.; Niccolai, S.; Niculescu, G.; Niculescu, I.; Osipenko, M.; Ostrovidov, A. I.; Paolone, M.; Paremuzyan, R.; Park, K.; Pasyuk, E.; Peng, P.; Pisano, S.; Pogorelko, O.; Price, J. W.; Puckett, A. J. R.; Raue, B. A.; Rizzo, A.; Rosner, G.; Rossi, P.; Roy, P.; Sabatié, F.; Salgado, C.; Schumacher, R. A.; Sharabian, Y. G.; Skorodumina, I. u.; Smith, G. D.; Sokhan, D.; Sparveris, N.; Stankovic, I.; Strakovsky, I. I.; Strauch, S.; Taiuti, MAURO GINO; Tian, Ye; Ungaro, M.; Voskanyan, H.; Voutier, E.; Walford, N. K.; Watts, D. P.; Wei, X.; Weinstein, L. B.; Wood, M. H.; Zachariou, N.; Zhang, J.; Zonta, I.

doi:10.1103/PhysRevC.94.045206

We report measurements of target- and double-spin asymmetries for the exclusive channel e- p - →eπ+(n) in the nucleon resonance region at Jefferson Lab using the CEBAF Large Acceptance Spectrometer (CLAS). These asymmetries were extracted from data obtained using a longitudinally polarized NH3 target and a longitudinally polarized electron beam with energies 1.1, 1.3, 2.0, 2.3, and 3.0 GeV. The new results are consistent with previous CLAS publications but are extended to a low Q2 range from 0.0065 to 0.35(GeV/c)2. The Q2 access was made possible by a custom-built Cherenkov detector that allowed the detection of electrons for scattering angles as low as 6°. These results are compared with the unitary isobar models JANR and MAID, the partial-wave analysis prediction from SAID, and the dynamic model DMT. In many kinematic regions our results, in particular results on the target asymmetry, help to constrain the polarization-dependent components of these models.

Measurement of target and double-spin asymmetries for the ep - →eπ+(n) reaction in the nucleon resonance region at low Q2

Zheng, X.;Adhikari, K. P.;Bosted, P.;Deur, A.;Drozdov, V.;El Fassi, L.;Kang, Hyekoo;Kovacs, K.;Kuhn, S.;Long, E.;Phillips, S. K.;Ripani, M.;Slifer, K.;Smith, L. C.;Adikaram, D.;Akbar, Z.;Amaryan, M. J.;Anefalos Pereira, S.;Asryan, G.;Avakian, H.;Badui, R. A.;Ball, J.;Baltzell, N. A.;Battaglieri, M.;Batourine, V.;Bedlinskiy, I.;Biselli, A. S.;Briscoe, W. J.;Bültmann, S.;Burkert, V. D.;Carman, D. S.;Celentano, A.;Chandavar, S.;Charles, G.;Chen, J. P.;Chetry, T.;Choi, Seonho;Ciullo, G.;Clark, L.;Colaneri, L.;Cole, P. L.;Compton, N.;Contalbrigo, M.;Crede, V.;D'Angelo, A.;Dashyan, N.;De Vita, R.;De Sanctis, E.;Djalali, C.;Dodge, G. E.;Dupre, R.;Egiyan, H.;El Alaoui, A.;Elouadrhiri, L.;Eugenio, P.;Fanchini, E.;Fedotov, G.;Fersch, R.;Filippi, A.;Fleming, J. A.;Gevorgyan, N.;Ghandilyan, Y.;Gilfoyle, G. P.;Giovanetti, K. L.;Girod, F. X.;Gleason, C.;Golovach, E.;Gothe, R. W.;Griffioen, K. A.;Guidal, M.;Guler, N.;Guo, L.;Hanretty, C.;Harrison, N.;Hattawy, M.;Hicks, K.;Holtrop, M.;Hughes, S. M.;Ilieva, Y.;Ireland, D. G.;Ishkhanov, B. S.;Isupov, E. L.;Jenkins, D.;Jiang, H.;Jo, H. S.;Joosten, S.;Keller, D.;Khachatryan, G.;Khandaker, M.;Kim, A.;Kim, W.;Klein, F. J.;Kubarovsky, V.;Lanza, L.;Lenisa, P.;Livingston, K.;Macgregor, I. J. D.;Markov, N.;Mckinnon, B.;MIRAZITA, MARCO;Mokeev, V.;Movsisyan, A.;Munevar, E.;Munoz Camacho, C.;Murdoch, G.;Nadel Turonski, P.;Net, L. A.;Ni, A.;Niccolai, S.;Niculescu, G.;Niculescu, I.;Osipenko, M.;Ostrovidov, A. I.;Paolone, M.;Paremuzyan, R.;Park, K.;Pasyuk, E.;Peng, P.;Pisano, S.;Pogorelko, O.;Price, J. W.;Puckett, A. J. R.;Raue, B. A.;Rizzo, A.;Rosner, G.;Rossi, P.;Roy, P.;Sabatié, F.;Salgado, C.;Schumacher, R. A.;Sharabian, Y. G.;Skorodumina, I.u.;Smith, G. D.;Sokhan, D.;Sparveris, N.;Stankovic, I.;Strakovsky, I. I.;Strauch, S.;TAIUTI, MAURO GINO;Tian, Ye;Ungaro, M.;Voskanyan, H.;Voutier, E.;Walford, N. K.;Watts, D. P.;Wei, X.;Weinstein, L. B.;Wood, M. H.;Zachariou, N.;Zhang, J.;Zonta, I.

2016-01-01

Abstract

We report measurements of target- and double-spin asymmetries for the exclusive channel e- p - →eπ+(n) in the nucleon resonance region at Jefferson Lab using the CEBAF Large Acceptance Spectrometer (CLAS). These asymmetries were extracted from data obtained using a longitudinally polarized NH3 target and a longitudinally polarized electron beam with energies 1.1, 1.3, 2.0, 2.3, and 3.0 GeV. The new results are consistent with previous CLAS publications but are extended to a low Q2 range from 0.0065 to 0.35(GeV/c)2. The Q2 access was made possible by a custom-built Cherenkov detector that allowed the detection of electrons for scattering angles as low as 6°. These results are compared with the unitary isobar models JANR and MAID, the partial-wave analysis prediction from SAID, and the dynamic model DMT. In many kinematic regions our results, in particular results on the target asymmetry, help to constrain the polarization-dependent components of these models.